This invention relates to a latch for sliding doors or windows by which it is possible to lock the moveable sliding door or window in any of a number of intermediate positions between fully open and closed. A number of prior art devices are known in which a limited number of open locked positions are possible by the use of locking pins in opposed holes. One such arrangement is shown in U.S. Pat. No. 3,779,588 issued to R. T. Raymon for "Sliding Panel Lock" on Dec. 18, 1973. The number of locked positions is quite limited in this system by nature of its structure.
A number of pivoted locking mechanisms having biting tooth portions are further known to restrain the movement of window relative to frame. Several such arrangements are shown in the prior art. U.S. Pat. No. 2,254,167 issued on Aug. 26, 1941 to W. C. Carpenter for "Window Catch" shows one pivotal biting type latch operable with vertically moveable windows.
U.S. Pat. No. 2,202,952 issued on June 4, 1940 to C. Z. Hayes for "Window Sash Fastener or Holder" discloses a still further type of pivotal catch used for latching a vertically moveable window.
Further arrangements are known for locking sliding glass doors against relative motion between it and the frame in which a projection and keeper are used for locking the door in its closed position. Such an arrangement likewise does not permit locking of the door in any of a large number of selected open positions which may be desired. One such arrangement of this type is shown in U.S. Pat. No. 3,830,534 issued on Aug. 20, 1974 to H. L. Pettrie et al. for "Lock for a Sliding Glass Door". It likewise does not prevent against "window lift" in the simple but effective manner of applicant's latch.